maybe he interfere through using avatars? Like how he possess the bodies? Talking as an ORV fan here :)
Tru this approach:
Think of the mc n everyone else that entered the tower as players, the tower master on the other hand being the crucial npc to the game (endings, route, etc) and the system is well the system of the game, so who r the constellations? Yep, the support npcs that gives side quest. So the constellations can't directly interfere with the story flow though they r far stronger than the tower master.
This new world feels like sequel to her previous live right? N this world (novel) is unfinished. Just my opinion ╮(￣▽￣)╭
I'm really wondering how could the "Tower's Master" can interfere and intervene in this world yet those "Constellations" cannot?
Anyone who read the LN? Care to explain